In June last year, North Korean troops violated the border three times, prompting South Korea to fire warning shots. The incidents occurred when the Koreas were embroiled in Cold War-style campaigns like balloon launches and propaganda broadcasts, but they didn’t develop into a major source of tensions.

"Our military issued warnings and fired warning shots, and the North Korean soldiers retreated," a South Korean Joint Chiefs of Staff official told reporters.

SEOUL, South Korea -- South Korea says its military has fired warning shots after North Korean soldiers crossed the border. South Korea’s military said about 10 North Korean soldiers returned to the North’s territory after South Korea fired made warning broadcasts and fired warning shots.